CD44 and neoplasm: To investigate the mechanism underlying the superior abilities of tumour initiation, formation, invasion and metastasis of the ALDH+ CD44+ CXCR4+ CD24+ subpopulation, we performed microarray analysis to identify the DEGs between the ALDH+ CD44+ CXCR4+ CD24+- and ALDH− CD44− CXCR4− CD24−-PCa cells.